Polyether-containing double metal cyanide catalysts

ABSTRACT

Improved double metal cyanide (DMC) catalysts are disclosed. The catalysts comprise a DMC compound, an organic complexing agent, and from about 5 to about 80 wt. % of a polyether polyol that has tertiary hydroxyl groups. Compared with other DMC catalysts, those of the invention have excellent activity for epoxide polymerization, and they can be used to make polyols having very low unsaturation even at high epoxide polymerization temperatures.

This is a division of Appl. Ser. No. 08/517,780, filed Aug. 22, 1995,now allowed as U.S. Pat. No. 5,545,601.

FIELD OF THE INVENTION

The invention relates to double metal cyanide (DMC) catalysts useful forepoxide polymerization. In particular, the invention relates to DMCcatalysts that have high activity and that give very low unsaturationpolyols even at relatively high epoxide polymerization temperatures.

BACKGROUND OF THE INVENTION

Double metal cyanide complexes are well-known catalysts for epoxidepolymerization. These active catalysts give polyether polyols that havelow unsaturation compared with similar polyols made using basic (KOH)catalysis. The catalysts can be used to make many polymer products,including polyether, polyester, and polyetherester polyols. The polyolscan be used in polyurethane coatings, elastomers, sealants, foams, andadhesives.

DMC catalysts are usually made by reacting aqueous solutions of metalsalts and metal cyanide salts to form a precipitate of the DMC compound.A low molecular weight complexing agent, typically an ether or analcohol is included in the catalyst preparation. The complexing agent isneeded for favorable catalyst activity. Preparation of typical DMCcatalysts is described, for example, in U.S. Pat. Nos. 3,427,256,3,829,505, and 5,158,922.

We recently described highly active DMC catalysts that include, inaddition to a low molecular weight organic complexing agent, from about5 to about 80 wt. % of a polyether having a molecular weight greaterthan about 500 (see U.S. Pat. No. 5,482,908). Excellent results areobtained when the polyether component of the DMC catalyst is apolyoxypropylene polyol. Compared with earlier DMC catalysts, thepolyether-containing DMC catalysts have excellent activity and givepolyether polyols with very low unsaturation. In addition,polyether-containing DMC catalysts such as those described in the `908`patent are easier to remove from the polyol products following epoxidepolymerization.

The polyether-containing DMC catalysts that we described earlier arevaluable because they give polyether polyols with low unsaturation, andthey are active enough to allow their use at very low concentrations,often low enough to overcome any need to remove the catalyst from thepolyol. Catalysts with even higher activity are desirable becausereduced catalyst levels could be used.

One drawback of polyether-containing DMC catalysts now known (and DMCcatalysts generally) is that polyol unsaturations increase with epoxidepolymerization temperature. Thus, polyols prepared at higher reactiontemperatures (usually to achieve higher reaction rates) tend to haveincreased unsaturation levels. This sensitivity of unsaturation toincreases in epoxide polymerization temperature is preferably minimizedor eliminated.

An ideal catalyst would give polyether polyols with low unsaturation andwould be active enough to use at very low concentrations, preferably atconcentrations low enough to overcome any need to remove the catalystfrom the polyol. Particularly valuable would be a catalyst that canproduce polyether polyols having very low unsaturation levels over abroad range of epoxide polymerization temperatures.

SUMMARY OF THE INVENTION

The invention is a solid double metal cyanide (DMC) catalyst useful forepoxide polymerizations. The catalyst comprises a DMC compound, anorganic complexing agent, and from about 5 to about 80 wt. % of apolyether polyol. Some or all of the hydroxyl groups of the polyetherpolyol are tertiary hydroxyl groups. The invention also includes amethod for making the catalysts, and a process for making epoxidepolymers using the catalysts.

I surprisingly found that DMC catalysts that include a tertiary hydroxylgroup-containing polyol have excellent activity. In addition, thecatalysts of the invention can be used to make polyols having very lowunsaturations even at relatively high epoxide polymerizationtemperatures. The reduced sensitivity of unsaturation to reactiontemperature allows for efficient production of polyether polyols whilemaintaining high product quality.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a plot of propylene oxide consumption versus time during apolymerization reaction with one of the catalyst compositions of theinvention (see Example 6) at 100 ppm catalyst and 105° C.

DETAILED DESCRIPTION OF THE INVENTION

Double metal cyanide compounds useful in the invention are the reactionproducts of a water-soluble metal salt and a water-soluble metal cyanidesalt. The water-soluble metal salt preferably has the general formulaM(X)_(n) in which M is selected from the group consisting of Zn(II),Fe(II), Ni(II), Mn(II), Co(II), Sn(II), Pb(II), Fe(II), Mo(IV), Mo(VI),Al(III), V(V), V(IV), Sr(II), W(IV), W(VI), Cu(II), and Cr(III). Morepreferably, M is selected from the group consisting of Zn(II), Fe(II),Co(II), and Ni(II). In the formula, X is preferably an anion selectedfrom the group consisting of halide, hydroxide, sulfate, carbonate,cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate, carboxylate,and nitrate. The value of n is from 1 to 3 and satisfies the valencystate of M. Examples of suitable metal salts include, but are notlimited to, zinc chloride, zinc bromide, zinc acetate, zincacetonylacetate, zinc benzoate, zinc nitrate, iron(II) sulfate, iron(II)bromide, cobalt(II) chloride, cobalt(II) thiocyanate, nickel(II)formate, nickel(II) nitrate, and the like, and mixtures thereof.

The water-soluble metal cyanide salts used to make the double metalcyanide compounds useful in the invention preferably have the generalformula (Y)_(a) M'(CN)_(b) (A)_(c) in which M' is selected from thegroup consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III),Mn(II), Mn(III), Ir(III), Ni(II), Rh(III), Ru(II), V(IV), and V(V). Morepreferably, M' is selected from the group consisting of Co(II), Co(III),Fe(II), Fe(III), Cr(III), Ir(III), and Ni(II). The water-soluble metalcyanide salt can contain one or more of these metals. In the formula, Yis an alkali metal ion or alkaline earth metal ion. A is an anionselected from the group consisting of halide, hydroxide, sulfate,carbonate, cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate,carboxylate, and nitrate. Both a and b are integers greater than orequal to 1; the sum of the charges of a, b, and c balances the charge ofM'. Suitable water-soluble metal cyanide salts include, but are notlimited to, potassium hexacyanocobaltate(III), potassiumhexacyanoferrate(II), potassium hexacyanoferrate(III), calciumhexacyanocobaltate(III), lithium hexacyanoiridate(III), and the like.

Examples of double metal cyanide compounds that can be used in theinvention include, for example, zinc hexacyanocobaltate(III), zinchexacyanoferrate(III), zinc hexacyanoferrate(II), nickel(II)hexacyanoferrate(II), cobalt(II) hexacyanocobaltate(III), and the like.Further examples of suitable double metal cyanide compounds are listedin U.S. Pat. No. 5,158,922, the teachings of which are incorporatedherein by reference.

The solid DMC catalysts of the invention include an organic complexingagent. Generally, the complexing agent must be relatively soluble inwater. Suitable complexing agents are those commonly known in the art,as taught, for example, in U.S. Pat. No. 5,158,922. The complexing agentis added either during preparation or immediately followingprecipitation of the catalyst. Usually, an excess amount of thecomplexing agent is used. Preferred complexing agents are water-solubleheteroatom-containing organic compounds that can complex with the doublemetal cyanide compound. Suitable complexing agents include, but are notlimited to, alcohols, aldehydes, ketones, ethers, esters, amides, ureas,nitriles, sulfides, and mixtures thereof. Preferred complexing agentsare water-soluble aliphatic alcohols selected from the group consistingof ethanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol,sec-butyl alcohol, and tert-butyl alcohol. Tert-butyl alcohol is mostpreferred.

The solid DMC catalysts of the invention include from about 5 to about80 wt. % of a polyether polyol. Some or all of the hydroxyl groups ofthe polyether polyol are tertiary hydroxyl groups. Preferred catalystsinclude from about 10 to about 70 wt. % of the polyether polyol; mostpreferred catalysts include from about 15 to about 60 wt. % of thepolyether polyol. At least about 5 wt. % of the polyether polyol isneeded to significantly improve the catalyst activity compared with acatalyst made in the absence of the polyether polyol. Catalysts thatcontain more than about 80 wt. % of the polyether polyol are generallyno more active, and they are impractical to isolate and use because theyare typically sticky pastes rather than powdery solids.

Polyether polyols suitable for use in making the catalysts of theinvention have at least some tertiary hydroxyl groups. Preferredpolyether polyols have at least about 5 % tertiary hydroxyl groups; morepreferred are polyols that have at least about 20 % tertiary hydroxylgroups.

The polyols used in the catalysts can be made by any suitable method.Polyether polyols made by ring-opening polymerization of cyclic ethers(epoxides, oxetanes, tetrahydrofurans) can be used. The polyols can bemade by any method of catalysis (acid, base, coordination catalyst).Tertiary hydroxyl groups are conveniently introduced by including acyclic ether monomer that is fully substituted at the s-carbon atom ofthe cyclic ether. Cyclic ethers useful for introducing tertiary hydroxylgroups include, for example, isobutylene oxide, 1,1,2-trimethylethyleneoxide, 1,1,2,2,-tetramethylethylene oxide, 2,2-dimethyloxetane,diisobutylene oxide, α-methylstyrene oxide, and the like. For example,one polyether polyol suitable for use in making the catalysts of theinvention is prepared by making a polyoxypropylene polyol using doublemetal cyanide catalysis, and then adding isobutylene oxide to cap thepolyol and convert some or most of the hydroxyl groups from primary orsecondary to tertiary hydroxyl groups.

Suitable polyether polyols include those in which tertiary hydroxylgroup content is introduced by including a lactone monomer in which thecarbon α- to the lactone oxygen is fully substituted. Thus, for example,a suitable polyol for use in the invention is made by reacting apolyoxypropylene polyol with ε, ε-dimethyl-εcaprolactone to cap thepolyol and give a product in which at least some of the hydroxyl groupsare tertiary hydroxyl groups.

Preferred polyether polyols for making the catalysts have averagehydroxyl functionalities from about 2 to 8, and number average molecularweights within the range of about 200 to about 10,000 (more preferablyfrom about 500 to about 5000). Most preferred are polyether diols andtriols having number average molecular weights from about 1000 to about4000.

Particularly preferred polyether polyols are polyoxypropylene diols andtriols capped with from about 1 to 5 isobutylene oxide units. Thesepolyols preferably have at least about 20% of tertiary hydroxyl groups.

Both an organic complexing agent and a polyether polyol are needed inthe double metal cyanide catalyst. Including the polyether polyol inaddition to the organic complexing agent enhances activity of thecatalyst compared with the activity of a similar catalyst prepared inthe absence of the polyether polyol. The organic complexing agent isalso needed: a catalyst made in the presence of the polyether polyol,but without an organic complexing agent such as tert-butyl alcohol, willnot polymerize epoxides.

I surprisingly found that the use of a polyether polyol having tertiaryhydroxyl groups further improves the catalyst compared with catalystsmade with an organic complexing agent and a polyether polyol that doesnot have tertiary hydroxyl groups. The catalysts of the invention havehigh activity for polymerizing epoxides, and they can be used to makepolyols having very low unsaturations even at relatively high epoxidepolymerization temperatures.

As the results in Table 1 (below) show, the catalysts of the inventionhave excellent activity for polymerizing epoxides--as good as or betterthan catalysts made with polyols that have no tertiary hydroxyl groups.In addition, the catalysts of the invention give polyol products havinglow unsaturation even at relatively high epoxide polymerizationtemperatures. Compare Examples 1 and 2 with Comparative Examples 9 and10. These examples show that raising epoxide polymerization temperatureto 150° C. has a reduced impact on polyol unsaturation when a catalystof the invention is used.

The invention includes a method for making the catalysts. The methodcomprises preparing a solid DMC catalyst in the presence of an organiccomplexing agent and a polyether polyol that contains tertiary hydroxylgroups. Aqueous solutions of a metal salt (excess) and a metal cyanidesalt are reacted in the presence of the organic complexing agent and thepolyether polyol. The polyether polyol is used in an amount sufficientto produce a solid DMC catalyst that contains from about 5 to about 80wt. % of the polyether polyol.

In a typical method, aqueous solutions of a metal salt (such as zincchloride) and a metal cyanide salt (such as potassiumhexacyanocobaltate) are first reacted in the presence of an organiccomplexing agent (such as tert-butyl alcohol) using efficient mixing toproduce a catalyst slurry. The metal salt is used in excess. Thecatalyst slurry contains the reaction product of the metal salt andmetal cyanide salt, which is the double metal cyanide compound. Alsopresent are excess metal salt, water, and organic complexing agent; eachis incorporated to some extent in the catalyst structure.

The organic complexing agent can be included with either or both of thethe aqueous salt solutions, or it can be added to the catalyst slurryimmediately following precipitation of the DMC compound. It is generallypreferred to pre-mix the complexing agent with either aqueous solution,or both, before combining the reactants. If the complexing agent isadded to the catalyst precipitate instead, then the reaction mixtureshould be mixed efficiently with a homogenizer or a high-shear stirrerto produce the most active form of the catalyst.

The catalyst slurry produced as described above is combined with thepolyether polyol having tertiary hydroxyl groups. This is preferablydone using low-shear mixing to avoid thickening or coagulation of thereaction mixture. The polyether-containing catalyst is then usuallyisolated from the catalyst slurry by any convenient means, such asfiltration, centrifugation, decanting, or the like.

The isolated polyether-containing solid catalyst is preferably washedwith an aqueous solution that contains additional organic complexingagent. Washing is generally accomplished by reslurrying the catalyst inthe aqueous solution of organic complexing agent, followed by a catalystisolation step. The washing step removes impurities that can render thecatalyst inactive if they are not removed. Preferably, the amount oforganic complexing agent used in this aqueous solution is within therange of about 40 wt. % to about 70 wt. %. It is also preferred toinclude some polyether polyol in the aqueous solution of organiccomplexing agent. The amount of polyether polyol in the wash solution ispreferably within the range of about 0.5 to about 8 wt. %.

While a single washing step suffices, it it generally preferred to washthe catalyst more than once. The subsequent wash can be a repeat of thefirst wash. Preferably, the subsequent wash is non-aqueous, i.e., itincludes only the organic complexing agent or a mixture of the organiccomplexing agent and polyether polyol. After the catalyst has beenwashed, it is usually preferred to dry it under vacuum until thecatalyst reaches a constant weight.

The invention includes a process for making an epoxide polymer. Thisprocess comprises polymerizing an epoxide in the presence of a doublemetal cyanide catalyst of the invention. Preferred epoxides are ethyleneoxide, propylene oxide, butene oxides, styrene oxide, and the like, andmixtures thereof. The process can be used to make random or blockcopolymers. The epoxide polymer can be, for example, a polyether polyolderived from the polymerization of an epoxide in the presence of ahydroxyl group-containing initiator.

Other monomers that will copolymerize with an epoxide in the presence ofa DMC compound can be included in the process of the invention to makeother types of epoxide polymers. Any of the copolymers known in the artmade using conventional DMC catalysts can be made with the catalysts ofthe invention. For example, epoxides copolymerize with oxetanes (astaught in U.S. Pat. Nos. 3,278,457 and 3,404,109) to give polyethers, orwith anhydrides (as taught in U.S. Pat. Nos. 5,145,883 and 3,538,043) togive polyester or polyetherester polyols. The preparation of polyether,polyester, and polyetherester polyols using double metal cyanidecatalysts is fully described, for example, in U.S. Pat. Nos. 5,223,583,5,145,883, 4,472,560, 3,941,849, 3,900,518, 3,538,043, 3,404,109,3,278,458, 3,278,457, and in J. L. Schuchardt and S. D. Harper, SPIProceedings, 32nd Annual Polyurethane Tech./Market. Conf. (1989) 360.The teachings of these U.S. patents related to polyol synthesis usingDMC catalysts are incorporated herein by reference in their entirety.

Polyether polyols made with the catalysts of the invention preferablyhave average hydroxyl functionalities from about 2 to 8, more preferablyfrom about 2 to 6, and most preferably from about 2 to 3. The polyolspreferably have number average molecular weights within the range ofabout 500 to about 50,000. A more preferred range is from about 1,000 toabout 12,000; most preferred is the range from about 2,000 to about8,000.

The following examples merely illustrate the invention. Those skilled inthe art will recognize many variations that are within the spirit of theinvention and scope of the claims.

EXAMPLE A

Preparation of a Solid DMC Catalyst containing tert-Butyl Alcohol and anIsobutylene oxide-capped 4K mol. wt. Polyoxypropylene Diol

Potassium hexacyanocobaltate (8.0 g) is dissolved in deionized (DI)water (140 mL) in a beaker (Solution 1). Zinc chloride (25 g) isdissolved in DI water (40 mL) in a second beaker (Solution 2). A thirdbeaker contains Solution 3: a mixture of DI water (200 mL), tert-butylalcohol (2 mL), and Polyol W (8 g). Polyol W is made by preparing a 4000mol. wt. polyoxypropylene diol using via double metal cyanide catalysis(Polyol X), and then endcapping it with from 1 to 5 equivalents perhydroxyl group of isobutylene oxide using the same DMC catalyst.

Solutions 1 and 2 are mixed together using a homogenizer. Immediately, a50/50 (by volume) mixture of tert-butyl alcohol and DI water (200 mLtotal) is added to the zinc hexacyanocobaltate mixture, and the productis homogenized for 10 min.

Solution 3 (the polyol/water/tert-butyl alcohol mixture) is added to theaqueous slurry of zinc hexacyanocobaltate, and the product is stirredmagnetically for 2 min. The mixture is filtered under pressure through a5-μm filter to isolate the solids.

The solid cake is reslurried in tert-butyl alcohol (140 mL) and DI water(60 mL), and the mixture is homogenized for 10 min. A solution of DIwater (200 mL) and additional Polyol W (2 g) is added, and the mixtureis stirred magnetically for 2 min. and filtered as described above.

The solid cake is reslurried in tert-butyl alcohol (200 mL) and ishomogenized for 10 min. Polyol W (1 g) is added, and the mixture isstirred magnetically for 2 min. and filtered. The resulting solidcatalyst is dried under vacuum at 50° C. (30 in. Hg) to constant weight.The yield of dry, powdery catalyst is about 10 g.

Elemental, thermogravimetric, and mass spectral analyses of the solidcatalyst show: polyol=18.0 wt. %; tert-butyl alcohol=9.0 wt. %; cobalt=9.5 wt. %; zinc=20.1 wt. %.

The catalyst described above is used to make the polyether polyols ofExamples 1 and 2 (see Table 1 ).

A similar procedure is used to make additional catalysts that contain 23or 50 wt. % of Polyol W, and these catalysts are used for Examples 3-8(see Table 1 ).

A control catalyst, which is used in Comparative Examples 9 and 10, ismade as in Example A, except that Polyol X (a 4000 molecular weightpolyoxypropylene diol made by DMC catalysis) is used instead of PolyolW, and the resulting catalyst contains 34 wt. % of Polyol X.

EXAMPLE C

Epoxide Polymerizations: Rate Experiments-General Procedure

A one-liter stirred reactor is charged with polyoxypropylene triol (700mol. wt.) starter (70 g) and polyol-containing zinc hexacyanocobaltatecatalyst (0.057 g, 100 ppm level in finished polyol). The mixture isstirred and heated to 105° C., and is stripped under vacuum to removetraces of water from the triol starter. The reactor pressure is adjustedto a vacuum of about 30 in. (Hg), and propylene oxide (10-11 g) is addedin one portion. The reactor pressure is then monitored carefully.Additional propylene oxide is not added until an accelerated pressuredrop occurs in the reactor; the pressure drop is evidence that thecatalyst has become activated. When catalyst activation is verified, theremaining propylene oxide (490 g) is added gradually to keep the reactorpressure at about 10 psig. After propylene oxide addition is complete,the mixture is held at 105° C. until a constant pressure is observed.Residual unreacted monomer is then stripped under vacuum from the polyolproduct, and the polyol is cooled and recovered.

To determine reaction rate, a plot of PO consumption (g) vs. reactiontime (min) is prepared (see FIG. 1 ). The slope of the curve at itssteepest point is measured to find the reaction rate in grams of POconverted per minute. The intersection of this line and a horizontalline extended from the baseline of the curve is taken as the inductiontime (in minutes) required for the catalyst to become active. Measuredreaction rates are summarized in Table 1.

When this procedure is used to measure propylene oxide polymerizationrates, the catalysts of the invention typically polymerize PO at ratesin excess of about 10 g/min at 100 ppm catalyst at 105° C. (see FIG. 1). The epoxide polymerization rates for the catalysts of the invention(which include a polyether polyol having tertiary hydroxyl groups) arealso consistently higher than similar catalysts prepared in the presenceof polyether polyols without tertiary hydroxyl groups. This procedure isused to prepare the 6000 molecular weight polyether triols (6K-T) shownin Table 1 using a 700 mol. wt. polyoxypopylene triol starter. (SeeExamples 1, 3, and 6, and Comparative Example 9.)

EXAMPLE D

Polyether Polyol Synthesis: 8000 Mol. Wt. Polyoxypropylene Diol (8K-D)

A one-liter stirred reactor is charged with polyoxypropylene diol (1000mol. wt.) starter (77 g) and zinc hexacyanocobaltate catalyst (0.015 g,25 ppm). The mixture is stirred and heated to 105° C., and is strippedunder vacuum for 0.5 h to remove traces of water from the diol starter.After stripping, the reaction temperature is raised to 145° C. Propyleneoxide (12 g) is fed to the reactor, initially under a vacuum of about 30in. (Hg), and the reactor pressure is monitored carefully. Additionalpropylene oxide is not added until an accelerated pressure drop occursin the reactor; the pressure drop is evidence that the catalyst hasbecome activated. When catalyst activation is verified, the remainingpropylene oxide (512 g) is added gradually over about 4 h. Afterpropylene oxide addition is complete, the mixture is held at 145° C.until a constant pressure is observed. Residual unreacted monomer isthen stripped under vacuum at 60° C. from the polyol product. (SeeExamples 2, 4, 5, 7, and 8, and Comparative Example 10.)

The preceding examples are meant only as illustrations. The scope of theinvention is defined by the claims.

                                      TABLE 1                                     __________________________________________________________________________    Polyether-Containing Double Metal Cyanide Catalysts and                       Polyols Made Using the Catalysts                                                                            Product                                         Polyol in Catalyst                                                                         Epoxide Polymerization Conditions                                                              Polyol Characteristics                          Ex Type of                                                                            Amt. Temp Cat. level                                                                          Rate (g                                                                             Polyol                                                                            Unsat.                                      #  Polyol                                                                             (wt. %)                                                                            (°C.)                                                                       (ppm) PO/min)                                                                             made                                                                              (meq/g)                                                                            Mw/Mn                                  __________________________________________________________________________    1  W    18   105  100   22.7  6K-T                                                                              0.0046                                                                             1.20                                   2  W    18   150   25   --    8K-D                                                                              0.0074                                                                             1.16                                   3  W    50   105  100   21.7  6K-T                                                                              0.0047                                                                             1.19                                   4  W    50   120   25   --    8K-D                                                                              0.0065                                                                             1.41                                   5  W    50   130   25   --    8K-D                                                                              0.0076                                                                             1.22                                   6  W    23   105  100   29.4  6K-T                                                                              0.0043                                                                             1.15                                   7  W    23   145   25   --    8K-D                                                                              0.0068                                                                             1.07                                   8  W    23   145   10   --    8K-D                                                                              0.0072                                                                             1.15                                   C9 X    34   105  100   17.9  6K-T                                                                              0.0039                                                                             --                                     C10                                                                              X    34   150   25   --    8K-D                                                                              0.0114                                                                             1.45                                   __________________________________________________________________________     Polyols: W = IBOcapped 4K poly(PO) diol; X = 4K poly(PO) diol.                6KT = 6000 mol. wt. polyoxypropylene triol; 8KD = 8000 mol. wt.               polyoxypropylene diol.                                                   

I claim:
 1. A process for making an epoxide polymer, said processcomprising polymerizing an epoxide in the presence of a catalyst whichcomprises:(a) a double metal cyanide compound; (b) an organic complexingagent; and (c) from about 5 to about 80 wt. % of a polyether polyol;wherein some or all of the hydroxyl groups of the polyether polyol aretertiary hydroxyl groups.
 2. The process of claim 1 wherein the epoxideis selected from the group consisting of ethylene oxide, propyleneoxide, butene oxides, styrene oxide, and mixtures thereof.
 3. Theprocess of claim 1 wherein the double metal cyanide compound is a zinchexacyanocobaltate.
 4. The process of claim 1 wherein the organiccomplexing agent is a water-soluble aliphatic alcohol selected from thegroup consisting of ethanol, isopropyl alcohol, n-butyl alcohol,isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol.
 5. Theprocess of claim 1 wherein the organic complexing agent is tert-butylalcohol.
 6. The process of claim 1 wherein the polyether polyol is anisobutylene oxide-capped poly(oxypropylene) polyol having a numberaverage molecular weight within the range of about 200 to about 10,000.7. The process of claim 1 wherein the epoxide is polymerized in thepresence of a hydroxyl group-containing initiator to produce a polyetherpolyol.
 8. A process for making an epoxide polymer, said processcomprising polymerizing an epoxide in the presence of a catalyst whichcomprises:(a) zinc hexacyanocobaltate; (b) an organic complexing agentselected from the group consisting of ethanol, isopropyl alcohol,n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tert-butylalcohol; and (c) from about 5 to about 80 wt. % of a polyether polyol;wherein some or all of the hydroxyl groups of the polyether polyol aretertiary hydroxyl groups.
 9. The process of claim 8 wherein the epoxideis selected from the group consisting of ethylene oxide, propyleneoxide, butene oxides, styrene oxide, and mixtures thereof.
 10. Theprocess of claim 8 wherein the organic complexing agent is tert-butylalcohol.
 11. The process of claim 8 wherein the polyether polyol is anisobutylene oxide-capped poly(oxypropylene) polyol having a numberaverage molecular weight within the range of about 200 to about 10,000.12. The process of claim 8 wherein the epoxide is polymerized in thepresence of a hydroxyl group-containing initiator to produce a polyetherpolyol.